The present invention applies to any type of earth working or material handling bucket of the type attached to and carried, moved and manipulated by a motive power source such as a vehicular piece of construction or agricultural equipment, in contrast to wheeled earth scraper apparatus that are pulled or pushed in trailer fashion over the earth surface being worked. Such construction or agricultural equipment includes, but is not limited to loaders of the skid steered type as well as those having continuous tracks instead of wheels, to mini-payloaders and larger loader equipment, to farm equipment such as tractors, power shovels and backhoe equipment and other such types of earth and material working and handling equipment. The buckets used with such equipment vary in configuration but typically comprise an open top construction having a primary forward blade at one edge of the bucket that defines an open chamber for retainably holding and carrying the earth or material manipulated into the bucket. Those buckets mounted to the equipment for use primarily by pushing the bucket in a forward direction (commonly referred to as front-end loaders) typically have a triangular cross-section shape with a relatively flat bottom surface, two side walls and a back wall; whereas those buckets used by backhoe equipment and functionally mounted to dig and handle material by being pulled toward the equipment, can also be configured with an open front bucket configuration but can also define more rectangular four-sided material handling chambers with a primary blade portion being configured on that upper edge of the sidewall located closest to the supporting equipment. The principles of this invention apply equally well to both types of the above-described bucket configurations.
The buckets to which this invention applies are very versatile and are used to perform a great variety of earth and material moving and handling features, including for example scooping, loading and transporting material, back dragging a material surface, cutting into material banks, leveling, landscraping, grading, skid shoveling, backhoeing, excavating, scraping and the like. The above-described buckets are generally designed primarily for handling and moving or transporting large amounts of bulk material. However, the buckets are often used for many of the above-described tasks for which they are not optimally designed. For example, such buckets are not typically optimally designed for scraping or skimming, grading, or scarifying surface material. As used herein, the terms scraping and skimming will be used interchangeably to describe an operation wherein a “cut” of material of predetermined depth is removed from a surface over which the bucket is moved. With conventional bucket designs, when the primary blade of the bucket is used for scraping operations, the blade tends to dig into the material surface when the blade is advanced in a forward direction of the bucket, providing uneven material removal. Similarly, to perform grading or leveling operations with such buckets, the bottom of the bucket is typically placed on the ground surface and the bucket is dragged “backward” to pull earth and material behind the bucket. Typical buckets do not allow for significant material to be accumulated behind the bucket when used in this manner, and the rear surfaces of conventional buckets are not designed and reinforced for extended use in this manner. Alternatively, the bucket may be raised and tipped forward such that the bottom of the bucket is generally vertical to the ground surface and then lowered until the front blade engages the ground. The bucket is then dragged backwards to pull earth and soil behind the bucket for grading the material surface. Such operation places significant torque on the bucket and excessive wear and tear on the hydraulic cylinders and linkage that control the bucket rotation. Such inadequacies of conventional buckets have been recognized in the field, and a number of bucket design configurations have been proposed to address the above issues.
For example, designs have focused on configuring articulated buckets having pivotal clam-like cooperative portions that selectively open and close along their lateral widths, such as shown, for example, in U.S. Pat. No. 3,209,474. Such designs are fairly cumbersome and relatively expensive to implement, and do not optimally provide for simultaneous uniform scraping removal and retention of soil or material from a surface.
Other designs, such as shown in U.S. Pat. No. 3,209,475 provide a bucket having forward and rearward mounted scraper blades. The forward blade forms a front surface of and closes the front opening of the bucket such that it is not usable as a conventional front-end loader bucket. The bucket is articulated with respect to the rear blade and can be height adjusted relative to the rear blade to capture material scraped by the rear blade into the back of the bucket. Such design requires skilled operator coordination of the relative positions of the first and second blades and does not enable the bucket to be used for multipurpose loading and transporting functions through front-end loading thereof.
Other scraper designs, such as shown in U.S. Pat. No. 5,806,607 are configured as add-on special use devices for conventional bulldozer blades, or as special purpose skimming bucket configurations that do not provide for closure of the opening adjacent the rearward skimming blade when the bucket is used for loading or material carrying functions.
The above described devices are intended only to be representative configurations that are found in the art, and serve to exemplify the deficiencies of such designs for providing effective, simple, reliable and user-friendly multipurpose bucket configurations that can alternatively be used on-the-fly as a conventional front loading bucket and/or as a scraper that employs the same front loading bucket to collect the scraper removed material. The present invention addresses these and other shortcomings of such prior art bucket designs.
In certain excavation operations, such as in forming trenches for laying cylindrical pipelines, it is desirable and sometimes required that the bottom of the trench have a rounded or hemispherical cross-sectional shape that matches that of the pipe to be supported by the trench. A number of bucket configurations having specialized add-on or integral apparatus for forming the desired specialized cross-sectional trench shape are known in the art. Such designs, however, are generally cumbersome, often require work to be delayed while the special attachment is applied to the bucket, and generally do not provide the flexibility of use of the bucket for its primary intended excavation process when such trench shaping process is not needed or desired. The present invention also addresses the shortcomings of such prior art trenching bucket designs.